1. Field of the Invention
The present invention pertains to an infrared drying system, and more particularly, pertains to an infrared drying system utilizing a temperature sensor, moisture sensor, or other physical property sensor connected to a computer for generating moisture content and position signals across the width of a traveling web of material with respect to a set point, and controlling infrared lamps over predetermined time intervals of a power cycle for drying the web.
2. Description of the Prior Art
Prior art infrared drying systems have failed to provide for selective drying of a traveling web of material over predetermined time periods. Prior art systems have heated an entire traveling web or overlapping positions of the entire traveling web rather than selectively heating a particular portion or zone of a traveling web for a predetermined finite interval of time, particularly for time intervals of a power cycle.
The use of infrared radiation to dry webs is known. U.S. Pat. No. 4,693,013 to Pabst et al. discloses an infrared dryer for drying fabric webs. The radiators can be pivoted into a "waiting position" to direct the emitted radiation away from the web so that they can remain fully energized without burning the web once the web is dried, or without burning the web if it stops moving.
U.S. Pat. No. 4,015,340 to Treleven discloses ultraviolet radiating assemblies. Ultraviolet mercury quartz lamps are received within an elongated reflector having a generally elliptically shaped inside surface cross-section to focus the emitted light. The reflector includes a plurality of cooling fins. The reflector and lamps are supported by a reflector carrier, which is then slidably mounted in a lamp module. The module includes flat rectangular metal frame heat exchangers to assist in removing heat from the modules. The modules are encased in a housing having an exhaust chamber attached to a fan to pull air through the housing which also cools the components therein.
Typical prior art reflectors have poor resolution, in that they do not block the light between adjacent lamps. Thus, too large of a dissipation pattern of light results. Light from one lamp can affect areas four or five zones away. Controlling the drying of specific areas of the web by independently controlling individual lamps is extremely difficult where such a large dissipation pattern is present. The shape of the reflector is also important in avoiding reflector material degradation, including melting of the reflector.
The present invention overcomes the disadvantages of the prior art by providing an infrared drying system which senses the physical property value across the width of a traveling web and heats the traveling web with a module or unit of modules of infrared heaters to control the moisture or other physical property in the web according to an algorithm.